Well, if software testers refused to try to find bugs due to "etiquette" then there would be a lot more bugs. Tim Krabbe has amusing collection of over 30 chess games in which somebody resigned in a won position... sometimes even grandmaster, championship, and correspondence games... http://timkr.home.xs4all.nl/chess2/resigntxt.htm he then also had the groundbreaking notion of the "worst possible move" where you find a move such that your opponent is forced to win... whereas every other move you could make is a win for you even if you try not to... as a chess problemist goal. E.g. in this position https://timkr.home.xs4all.nl/chess2/c&h47.GIF white has 47 legal moves, 46 of which mate black, but if Qe7+ then black is forced to mate white in 1. And https://timkr.home.xs4all.nl/chess2/crusats178.GIF white has 178 legal moves, 177 of which force white to win even if he tries not to, but the 178th forces black to win even if he tries not to. I'm not advocating Lee Sedol keep playing hard to try to win. I'm advocating he just keep playing -- not even necessarily trying hard, just seeing whether alphago will go crazy. Alphago in the part of its training from strong human games must have had zero examples of play continuing beyond where humans would normally stop. It probably would not work, but beats resigning and would take near zero effort.... Krabbe also has a few examples of humans who figured out how to beat chess computers and other weird shit http://timkr.home.xs4all.nl/chess2/honor.htm